The present invention relates generally to systems and methods for locating objects, and in one exemplary application to asset locating systems.
Active Radio Frequency Identification (“RFID”) is presently in use today to locate assets. These assets are typically critical use or expensive items that are otherwise difficult or labor intensive to locate. Examples of RFID applications include location of assets in crowded factory environments, location of shipping containers and updating the location of a shipping container as the container is moved past different fixed RFID receiver stations, and location of critical medical equipment.
Existing RFID systems typically include transceivers and a computer or PC based application. The RFID transceivers use signal strength and round trip timing to get a rough triangulation of an article tagged with a RFID tag. Once the overall system (transceivers and PC based application) has been “trained” or calibrated to “know” the relative positional relationship between transceivers then the general area where the article is located can be found in a two dimensional manner, using a floor plan of the area, such as the article is located on the west side of incoming inspection area, or the article is located at dock #3. However, only limited article location capability is provided by existing RFID systems, and the information provided by existing RFID systems is only useful when the system also has access to a floor plan of the area.